kill a process started with popen

Question

After opening a pipe to a process with popen, is there a way to kill the process that has been started? (Using pclose is not what I want because th

Answer 1

Here is an improved version of popen2 (credit is due to Sergey L.). The version posted by slacy does not return the PID of the process created in popen2, but the PID assigned to sh.

pid_t popen2(const char **command, int *infp, int *outfp)
{
    int p_stdin[2], p_stdout[2];
    pid_t pid;

    if (pipe(p_stdin) != 0 || pipe(p_stdout) != 0)
        return -1;

    pid = fork();

    if (pid < 0)
        return pid;
    else if (pid == 0)
    {
        close(p_stdin[WRITE]);
        dup2(p_stdin[READ], READ);
        close(p_stdout[READ]);
        dup2(p_stdout[WRITE], WRITE);

        execvp(*command, command);
        perror("execvp");
        exit(1);
    }

    if (infp == NULL)
        close(p_stdin[WRITE]);
    else
        *infp = p_stdin[WRITE];

    if (outfp == NULL)
        close(p_stdout[READ]);
    else
        *outfp = p_stdout[READ];

    return pid;
}

The new version is to be called with

char *command[] = {"program", "arg1", "arg2", ..., NULL};

Answer 2

Actually if the process is doing I/O (which it should be, otherwise why popen instead of system(3)?), then pclose should whack it with a SIGPIPE the next time it tries to read or write, and it should fall over nicely :-)